1. Field
Embodiments relate to an optical system and a substrate sealing method.
2. Description of the Related Art
Recently, portable thin flat panel display devices have been used extensively as display devices. An electroluminescent display device is a self-light emitting type display device that has received attention as a next-generation display device due to its wide viewing angle, excellent contrast, and fast response rate. In addition, an organic light-emitting display device, in which an emissive layer is formed of an organic material, has advantages of excellent brightness, driving voltage, response rate properties, and the ability to provide a polychromatic image, compared to an inorganic light-emitting display device.
A typical organic light-emitting display device has a structure in which at least one organic layer, including an emissive layer, is interposed between a pair of electrodes.